This invention relates to power actuators for operating lock mechanisms of vehicle doors and other closures. Such power operated lock mechanisms commonly form part of a central locking system of the vehicle whereby locking or unlocking of some or all doors or other closures can be effected from a single control station actuated from within or outside the vehicle as by a coded infra-red or other remote input device. The lock mechanism and associated power actuator will provide for manual operation whereby the respective door can be locked and unlocked using a conventional interior sill button or other manually operated input. element, and, maybe, by manual operation of a cylinder or other key controlled exterior lock.
An advantageous form of power actuator is described and claimed in our British Patent Application No. 9521790.7 (230655 1) dated Oct. 24, 1995, said known type of actuator being hereinafter referred to as xe2x80x9cour previous manual override power actuatorxe2x80x9d.
The object of the present invention is to provide improvements in our previous manual override power actuator for more reliable performance, simplification of construction, and space saving by way of more compact arrangement.
According to the invention there is provided a power actuator for shifting a vehicle door lock or other closure mechanism selectively between a locked or other first condition and an unlocked or other second condition by powered operation while also permitting manual operation with the actuator providing positive indexing of manual shifting between said conditions, said actuator comprising:
a) an operatively fixed housing or other mounting;
b) a motor driven driver annulus journalled in or on said mounting for powered rotation and having interior control formations, a first set of said formations being within a first axial zone of the annulus and including spaced radially extending control notches separated by peripheral control lands, and a second set of said formations being within a second axial zone of the annulus and including a plurality of angularly spaced radially inwardly projecting camming lobes, each lobe being diametrally opposite but axially offset from a respective notch;
c) an elongate index element movable within the annulus, a head part of said element carrying a drive formation coacting with the first set of formations to transmit drive angularly displacing said element on powered rotation of the annulus and to provide said indexing by angular movement of said element relative to the stationary annulus during manual operation, and a tail part of said element carrying a stop formation coacting with the second set of control formations to regulate the displacement of the element relative to the annulus; and
d) an output element coupled to the index element and to the mechanism in use to transmit motion one to the other: characterised in that the tail part of the index element also carries a control projection co-acting with a control slot of the mounting extending radially of the axis of rotation of the annulus, said projection being offset further from the head part of the index element than the stop formation whereby the index element can swing angularly about the axis of said projection but its tail part is otherwise constrained for displacement radially of the annulus only with the offsetting providing leverage through the stop formation to ensure appropriate alignment of interacting parts of the element and annulus in operation
Conveniently the output element is a lever fulcrummed in or on the mounting and having one arm pivotally connected to the head part of the index element, for example directly engaged with an extension of the drive formation.
Preferably the index element is resiliently biased across the annulus in the general direction of the radially inner end of the control slot, for example in the case of the lever arm of the last preceding paragraph, by the drive formation extending into an elongate slot of the arm which also accommodates a spring urging said formation longitudinally of the arm.
The first set of control formations may be defined by a guide slot formation having a plurality, e.g. three, equi-angularly spaced arms extending radially of the annulus from a common center to provide a plurality, e.g. three, camming lobes therebetween and the drive formation will conveniently pin in sliding engagement in said slot formation.
The second set of control formations may comprise near parallel sided notches opening radially through the annulus periphery corresponding in number to said lobes, and peripheral lands between said notches having curved radially inwardly directed faces, the spacing of the drive formation from the stop formation being such that the index element is prevented by whichever face is in opposing relationship to the stop formation from longitudinal displacement out of engagement with a first control formation intermediate its extremes of travel during powered driving movement, but the disposition of the notches being such that the index element is aligned for unobstructed displacement in effecting said indexing during manual operation.